Stephen F. Nelsen

Learn More
Radical cations and dications of three bishydrazines belonging to the Class II mixed valence compounds have been generated, either spontaneously or by oxidation with AgSbF6, in two 1-butyl-3-methylimidazolium (4+) ionic liquids having BF4(-) and PF6(-) as counterions. The optical spectra of these intermediates have allowed evaluation of Marcus'(More)
Sixty-five electron-transfer reactions including 27 new 0, +1 couples have been added to our data set of cross-reactions between 0 and +1 couples, bringing it to 206 reactions involving 72 couples that have been studied by stopped-flow kinetics in acetonitrile containing supporting electrolyte at 25 degrees C, formal potentials determined by cyclic(More)
Electron-transfer cross-reactions between neutral molecules and their radical cations spanning a wide range of structural type and intrinsic reactivity have been analyzed using classical Marcus theory. The principal factor found to govern intrinsic reactivity is the inner-shell bond reorganization energy. The HOMO-LUMO overlap of alkyl groups on reacting(More)
The bicyclo[2.2.2]oct-2-ene radical cation (1(.+)) exhibits matrix ESR spectra that have two very different types of gamma-exo hydrogens (those hydrogens formally in a W-plan with the alkene pi bond), a(2H) about 16.9 G and a(2H) about 1.9 G, instead of the four equivalent hydrogens as would be the case in an untwisted C(2v) structure. Moreover, deuterium(More)
Excited state mixed valence (ESMV) occurs in molecules in which the ground state has a symmetrical charge distribution but the excited state possesses two or more interchangeably equivalent sites that have different formal oxidation states. Although mixed valence excited states are relatively common in both organic and inorganic molecules, their properties(More)
Resonance Raman scattering studies in the extended near-infrared region show that six modes are coupled to the intramolecular charge-transfer transition in the mixed-valence radical cation diazatetracyclodiene. Spectral analysis based on time-dependent scattering theories shows that all six modes make substantial contributions to the vibrational(More)
a We describe the logical flaws, experimental contradictions, and unfortunate educational repercussions of common student misconceptions regarding the shapes and properties of lone pairs, inspired by overemphasis on ''valence shell electron pair repulsion'' (VSEPR) rationalizations in current freshman-level chemistry textbooks. VSEPR-style representations(More)
[Figure: see text]. The optical spectra of 10 p-phenylene-bridged delocalized intervalence compounds MC6H4M*- or *+ are analyzed using the Koopmans-based method, which considers only transitions from filled orbitals to the singly occupied orbital (SOMO), called Hoijtink type A transitions, and from the SOMO to unoccupied orbitals, Hoijtink type B(More)
Resonance Raman spectroscopy, electronic absorption spectroscopy, and the time-dependent theory of spectroscopy are used to analyze the intervalence electron transfer properties of a strongly delocalized class III molecule, the tetraalkyl-p-phenylene diamine radical cation bis(3-oxo-9-azabicyclo[3.3.1]non-9-yl)benzene ((k33)(2)PD(+)). This molecule is a(More)